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Cloned human embryos deliver tailored stem cells

日期：2019-03-02 08:20:01 作者：刁咋 阅读：

By Rowan Hooper The paper discussed below was later found to have been based on fabricated data. Details of the official investigation into Woo Suk Hwang’s research, delivered by a panel from Seoul National University, was released on 10 January 2006. Click here for the story. The possibility of growing your own tissue or organs in the lab for transplantation is a step closer following experiments that successfully cloned patient-specific stem cells. Woo Suk Hwang, of Seoul National University, South Korea, and colleagues, used an improved technique for cloning embryos to create stem cell lines for 11 patients with various diseases or injuries. The lines exactly match the patients’ nuclear DNA and immune system. “This is an enormous stride in the long journey to determine whether nuclear transfer-derived human embryonic stem cells might be eventually suitable for transplantation medicine,” said Gerald Schatten, at the University of Pittsburgh School of Medicine, and a member of the team. Many technical hurdles must be overcome before spare organs could be successfully grown. But scientists will use the new approach to create human cell lines for research on diseases such as autism, diabetes and Parkinson’s. The cell lines will also be used to screen drugs – at present, screening is conducted using animals. Refining the techniques of human cloning for the development of new medical therapies could give encouragement to rogue scientists who wish to produce cloned babies. But the researchers insist this remains out of the question, both morally and scientifically. Hwang believes that human reproductive cloning is biologically impossible. And Mildred Cho, a biomedical ethicist at Stanford University, US, adds: “Irresponsible scientists might feel encouraged but there is no reason to believe this work significantly contributes to reproductive cloning.” The researchers extracted the nuclear DNA from skin cells of the 11 patients and inserted it into eggs donated by volunteers, having first emptied the eggs of their own DNA. The nuclear transfer technique is similar to that pioneered by the creators of Dolly the sheep at the Roslin Institute in Edinburgh, UK. The difference is that Hwang’s team’s process is far more efficient. Until recently it was not thought that nuclear transfer would even work in humans, but in 2004 Hwang’s team achieved it: They created 30 cloned human embryos and managed to harvest stem cells from one of them. Now, they have refined their technique and improved their efficiency tenfold, while also reducing their reliance on animal cells to feed the growing stem cells. “This paper has completely proven [adult] cell nuclear transfer as a technique in humans,” says Stephen Minger, of the Wolfson Centre for Age-Related Diseases, King’s College London, UK. In the US, eggs are in short supply and are often obtained from paid donors, but in Korea volunteers are plentiful. Eighteen women donated 185 eggs for research and, crucially, 125 of these were from women under the age of 30. The research suggests that it is the age of the egg donor which is important and not the age of the transferred DNA, which came from patients ranging in age from 2 to 56. Hwang’s laboratory is now way ahead of the field, says Minger, who recently visited the lab. They perfected their technique by performing some 1200 nuclear transfers every day on cells from sheep and cattle. Minger says that the quality of the science and the government support is as strong as anything he has seen in other labs and, in many cases, even better. “There is a good chance that the US will be left behind as the situation on stem cell research there becomes more fragmented and incoherent,” he adds. Journal reference: